//#pragma comment(linker,"/STACK:16777216") /*16Mb*/
//#pragma comment(linker,"/STACK:33554432") /*32Mb*/
#define _CRT_SECURE_NO_DEPRECATE
#include<iostream>
#include<numeric>
#include<sstream>
#include<cstdio>
#include<cstdlib>
#include<cmath>
#include<memory>
#include<string>
#include<vector>
#include<cctype>
#include<list>
#include<queue>
#include<deque>
#include<stack>
#include<map>
#include<set>
#include<algorithm>
using namespace std;

typedef unsigned long long      ui64;
typedef long long               i64;
typedef	vector<int>             VI;
typedef	vector<bool>            VB;
typedef	vector<VI>              VVI;
typedef	vector<string>          VS;
typedef	pair<int,int>           PII;
typedef map<string,int>         MSI;
typedef set<int>                SI;
typedef set<string>             SS;
typedef map<int,int>            MII;
typedef	pair<double,double>     PDD;

#define PB                      push_back
#define MP                      make_pair
#define X                       first
#define Y                       second
#define FOR(i, a, b)            for(int i = (a); i < (b); ++i)
#define RFOR(i, a, b)           for(int i = (a) - 1; i >= (b); --i)
#define CLEAR(a, b)             memset(a, b, sizeof(a))
#define SZ(a)                   int((a).size())
#define ALL(a)                  (a).begin(), (a).end()
#define RALL(a)                 (a).rbegin(), (a).rend()
#define INF                     (2000000000)


int main()
{
    int n,m; cin >> n >> m;
    VI a(n);
    int start = 0, k = 0;
    int _start = 0, _k = 0;
    FOR(i,0,n) {
        scanf("%d",&a[i]);

        if( a[start]+m >= a[i] )
            _k++;
        else {
            if( k<_k ) {
                start = _start;
                k = _k;
            }
			_k++;
			while( a[_start]+m<a[i] )
					{_start++;_k--;}
        }
    }
	if( k<_k ) {
        start = _start;
        k = _k;
    }
    cout << k << endl;
    FOR(i,0,k) {
        printf("%d",(n-i)/k + ( (n-i)%k ? 1 : 0) );
        for(int j=i;j<n;j+=k)
            printf(" %d",j+1);
        cout << endl;
    }
    
    return 0;
}